The matrix metalloproteinase-3 (MMP-3, stromelysin-1) exhibits a number of activities that would make it a particularly good tumor promoter. Like several other MMPs, MMP-3 was first cloned and later recloned as a cancer-specific gene. In addition to degrading numerous extracellular matrix components, MMP-3 can activate gelatinase B, the collagenases and several serpin-type serine proteinase inhibitors. Moreover, it can release a number of cell surface molecules, including E-cadherin, a known contributor to cancer development. In BioVision’s MMP-3 Inhibitor Screening Assay Kit, MMP-3 hydrolyzes a specific FRET substrate to release the quenched fluorescent group Mca, which can be detected fluorometrically at Em/Ex=325/393 nm. The kit provides a rapid, simple, sensitive, and reliable test suitable as a high throughput screening assay of MMP-3 inhibition. In addition, we also offer a human recombinant MMP-3 enzyme (Biovision #7783) and a MMP-3 Activity Assay Kit (Biovision #K783-100), separately.